Seismic fragility analysis of deteriorating recycled aggregate concrete bridge columns subjected to freeze-thaw cycles

In cold regions, concrete structural deterioration due to freeze-thaw damage is a common problem. To investigate the seismic performance of recycled aggregate concrete (RAC) members in a freeze-thaw environment, the seismic fragility analysis of RAC bridge columns with different recycled coarse aggregate (RCA) replacement ratios subjected to freeze-thaw cycles (FTCs) was performed by the cloud analysis method. The results show that, compared with peak ground acceleration, setting the peak ground velocity as the intensity measurement provided a better correlation with the damage measure when developing the probabilistic seismic demand model. Additionally, the fragility of all RAC bridge columns before FTCs were almost the same; as the FTCs increased, the fragility gradually increased and became increasingly significant as the RCA replacement ratios increased. Finally, the fragility analysis in this paper can provide a good reference for the seismic performance evaluation of RAC members in cold regions.